Field of the Invention
The present invention generally relates to an electromagnetic actuating device for actuating a medical device inserted into a human body. More particularly, the present invention relates to an electromagnetic actuating device able to efficiently supply actuation force to a medical device depending on the body shape of a subject, the body part to be diagnosed, and the actuating mechanism of the medical device.
Description of the Related Art
In general, medical devices are operated using wireless or wired actuations to diagnose or cure lesions present in internal organs, such as blood vessels and digestive organs. Among such medical devices, a miniature medical device inserted into a human body to be used for diagnosis may be difficult to control since it may not be suitable to be equipped with an on-board battery or an actuator.
Recently, studies of using magnetic fields to control miniature medical devices inserted into human bodies have been conducted. Medical devices are partially or entirely a magnetic material without a battery or a separate actuator such that they can be controlled using magnetic fields. When a battery or an actuator is replaced with a magnetic material, medical devices can be designed to have a very small size. Medical devices minimized in sizes allow for minimally invasive surgery. This minimizes the size of an incision during surgery, thereby advantageously reducing the pain and recovery periods of patients.
Medical devices having magnetic bodies can be controlled using a magnetic field generating apparatus disposed externally. The magnetic field generating apparatus is divided into a permanent magnet and an electromagnet. The permanent magnet can actuate a medical device by controlling the distance and the direction of magnetic field between the medical device and the permanent magnet. In this case, however, the movement and the rate of the medical device are limited, which are problematic.
Medical devices actuated using electromagnets can be controlled by applying currents to coils disposed externally in a fixed position. Here, it is possible to realize the intended actuation of medical devices by controlling, for example, the intensities and directions of currents applied to the coils. The use of electromagnets facilitates control compared to the use of permanent magnets. In addition, electromagnets can rapidly control the movement of medical devices depending on the characteristics of coils.
However, as a medical device becomes more distant away from an electromagnetic actuating device, the magnitude of magnetic field applying to the medical device is rapidly reduced. In this case, in order to control the medical device, a large amount of current must be applied to coils depending on the distance, which is problematic. More specifically, in a related-art electromagnetic actuating device for generating magnetic field toward a table on which a subject is lying, a coil is fixedly disposed. Thus, when the subject is diagnosed, the distance between the coil and the medical device changes depending on the body shape of the subject and the body part to be diagnosed. It is inefficient, in terms of control precision and power consumption, to control the amount of current applied to the coil considering the intensity of magnetic field changing depending on the distance.
In addition, in order to increase magnetic force, the electromagnet may be configured as a combination of a coil and a magnetic core. As described above, in order to increase magnetic force, a larger magnitude of magnetic force can be provided as the electromagnet (including the coil and the magnetic core) approaches the subject. Although the use of the magnetic core increases magnetic force, the magnetic core also increases the inductance of the electromagnet, whereby response to a change in magnetic field is delayed, which is problematic. When the medical device is actuated based on rotation, a rotating magnetic field is used. When a rapidly-changing magnetic field, such as a rotating magnetic field, is required, the magnetic core obstructs the actuation of the medical device, which is problematic.
In this case, it is advantageous for rotational actuation to place the coil part of the electromagnet to be close to the subject and set the position of the magnetic core behind the subject. Consequently, a structure allowing the relative positions of the coil and the magnetic core of the electromagnet to be adjusted and the overall position of the electromagnet (including the core and the magnetic core) to be changeable is advantageous for the actuation of the medical device. That is, an electromagnetic actuating device able to efficiently supply actuation force to a medical device depending on the body shape of a subject and the body part to be diagnosed, and the actuating mechanism of the medical device is required.
The information disclosed in the Background of the Invention section is only for the enhancement of understanding of the background of the invention, and should not be taken as an acknowledgment or as any form of suggestion that this information forms a prior art that would already be known to a person skilled in the art.